Integrated circuit device with a semiconductor body and method for the production of an integrated circuit device

ABSTRACT

An integrated circuit device with a semiconductor body and a method for the production of a semiconductor device a provided. The semiconductor body comprises a cell field with a drift zone of a first conduction type. In addition, the semiconductor device comprises an edge region surrounding the cell field. Field plates with a trench gate structure are arranged in the cell field, and an edge trench surrounding the cell field is provided in the edge region. The front side of the semiconductor body is in the edge region provided with an edge zone of a conduction type complementing the first conduction type with doping materials of body zones of the cell field. The edge zone of the complementary conduction type extends both within and outside the edge trench.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Utility patent application is a divisional application of U.S.application Ser. No. 12/020,077, filed Jan. 25, 2008, which claims thebenefit of the filing date of German Application No. DE 10 2007 061191.0, filed Dec. 17, 2007, which is herein incorporated by reference.

BACKGROUND

The application relates to an integrated circuit device with asemiconductor body and to a method for the production of an integratedcircuit device. The semiconductor body includes a cell field with adrift zone of a first conduction type. In addition, the semiconductordevice includes an edge region surrounding the cell field. Field plateswith a trench gate structure are arranged in the cell field.

In semiconductor devices with field plate compensation structures, thecell field is surrounded by an edge region for which an edge terminationhas to be provided. For this purpose, the active region, which isinitially completely free of a field oxide, is defined as a cell field.In the cell field, the field plates in the trench structure aresurrounded by a field plate insulation. The outer trenches or fieldplates of the cell field are provided with a field plate insulationwhich is brought out to a field oxide on the front side of thesemiconductor body in the edge region.

In addition, a continuous trench, a edge trench, surrounds the entirecell field, its clearance generally corresponding to the spacing of thetrench structures in the cell region.

Such a structure of a semiconductor device is subject to two types ofproblems. First, the edge trench is subjected to the highest loading, ascompensation is no longer complete on the side of the edge trench remotefrom the cell field. As a result, a breakdown may occur at thecontinuous edge trench, the location of the breakdown being thecurvature at the trench base adjacent to the cell field. There istherefore a risk that this edge breakdown may occur earlier than thecell field breakdown, so that the blocking capability of the edge trenchhas to be increased. A further problem is found in the region of thesource fingers with conductive contact material, as these contacts areonly provided outside the active cell field, leaving a certain minimumdistance between the end of the body zones and the continuous edgetrench.

In the region of the edge trench, the potential can directly reach thefield oxide from below in the semiconductor body, which could causeproblems. In principle, doping must not exceed a critical value,otherwise a potential breakdown at the trench base could jump upwards toa trench contact, whereby breakdown voltage is significantly reduced. Areduction of the concentration of doping material towards the surface,which is possible in an epitaxial process, slightly reduces the abilityof the potential to reach the field oxide while reducing the load on thecontinuous edge trench. The reduction of the concentration of dopingmaterial, however, adversely affects on resistance.

For these and other reasons, there is a need for the present invention.

SUMMARY

An integrated circuit device with a semiconductor body and a method forthe production of an integrated circuit device is provided. Thesemiconductor body includes a cell field with a drift zone of a firstconduction type. In addition, the semiconductor device includes an edgeregion surrounding the cell field. Field plates with a trench gatestructure are arranged in the cell field, while an edge trenchsurrounding the cell field is provided in the edge region. In the edgeregion, the front side of the semiconductor body includes an edge zoneof a conduction type complementing the first conduction type andidentical to the conduction type of the body zones of the cell field.The edge zone of the complementary conduction type extends both withinand outside the edge trench.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the present invention and are incorporated in andconstitute a part of this specification. The drawings illustrate theembodiments of the present invention and together with the descriptionserve to explain the principles of the invention. Other embodiments ofthe present invention and many of the intended advantages of the presentinvention will be readily appreciated as they become better understoodby reference to the following detailed description. The elements of thedrawings are not necessarily to scale relative to each other. Likereference numerals designate corresponding similar parts.

FIG. 1 illustrates a diagrammatic top view of a section of an integratedcircuit semiconductor device according to an embodiment.

FIG. 2 illustrates a schematic representation of a cross-section throughthe section of the semiconductor device 1 along line A-A through a fieldplate or trench structure.

FIG. 3 illustrates a perspective schematic representation of the sectionof the semiconductor device according to FIG. 1 along line A-A through abody zone or mesa structure.

FIG. 4 illustrates a diagrammatic cross-section through the section ofthe semiconductor device according to FIG. 1 along line B-B.

FIGS. 4 a to 4 c illustrate diagrammatic cross-sections through fieldplates in the cell field with different gate structures in the sametrench of the field plates.

FIGS. 5 to 12 illustrate diagrammatic cross-sections through fieldplates in the cell field with different gate structures in the sametrench of the field plates.

FIG. 5 illustrates a diagrammatic cross-section through a section of asemiconductor body after the introduction of trench structures.

FIG. 6 illustrates a diagrammatic cross-section through the section fromFIG. 5 after the application of an insulating layer.

FIG. 7 illustrates a diagrammatic cross-section through the section fromFIG. 6 after the trench structure has been filled with a conductivematerial.

FIG. 8 illustrates a diagrammatic cross-section through the section fromFIG. 7 after the removal of the conductive material from a field oxideon front sides of mesa structures.

FIG. 9 illustrates a diagrammatic cross-section through the section fromFIG. 8 after the application of a covering to the field oxide in theedge region.

FIG. 10 illustrates a diagrammatic cross-section through the sectionfrom FIG. 9 after the removal of the field oxide above the cell fieldand the etching in the trench.

FIG. 11 illustrates a diagrammatic cross-section through the sectionfrom FIG. 10 after the upper region of the trench structure has beenfilled with a conductive material. and

FIG. 12 illustrates a diagrammatic cross-section through the sectionfrom FIG. 11 after the ion implantation of body zones.

DETAILED DESCRIPTION

In the following Detailed Description, reference is made to theaccompanying drawings, which form a part hereof, and in which isillustrated by way of illustration specific embodiments in which theinvention may be practiced. In this regard, directional terminology,such as “top,” “bottom,” “front,” “back,” “leading,” “trailing,” etc.,is used with reference to the orientation of the Figure(s) beingdescribed. Because components of embodiments of the present inventioncan be positioned in a number of different orientations, the directionalterminology is used for purposes of illustration and is in no waylimiting. It is to be understood that other embodiments may be utilizedand structural or logical changes may be made without departing from thescope of the present invention. The following detailed description,therefore, is not to be taken in a limiting sense, and the scope of thepresent invention is defined by the appended claims.

FIG. 1 illustrates a diagrammatic top view of the layout of a section ofan integrated circuit semiconductor device 1 according to an embodiment.A strip-shaped trench structure 25 is formed in a cell field 4. Thiscell field 4 is surrounded by an edge trench 10 with a field plate 14.In this embodiment, an edge zone 12 extends both in the interior as aninner edge zone 35 and on the outside as an outer edge zone 34 and ischaracterised by a doping material of a complementary conduction typenear the surface of the semiconductor body 3, which is identical to thatof the body zones of the semiconductor device 1. This edge zone 12 isindicated in FIG. 1 by a hatching of broken lines and is, outside theedge trench 10, surrounded by a channel stopper region 17 indicated by ahatching of continuous lines bounded by the edge of the semiconductorchip.

This results not only in an outer edge zone 34 extending from the edgetrench 10 to the annular channel stopper 17, but also in an inner edgezone 35 extending from the edge trench 10 to the outer body zones 49 ofthe cell field 4.

The effect of such an inner edge zone 35, which extends from the edgetrench 10 along line A-A from FIG. 1 parallel to the cell field trenches25 to the outer body zones 49, is illustrated by a modified or improvedpotential profile which can be verified by simulation. The transitionfrom the active region of the cell field 4, this being the part of thecell field 4 where there are p-type body zones 13, is addressed. At thesame time, up to the edge termination of the MOS transistor withcompensation by field plates in trenches as illustrated by way ofexample in FIG. 1, there is no field oxide in this cell field 4.

The channel stopper 17 is at drain potential and is represented by apolysilicon field plate in this embodiment. This field plate also marksthe body implantation in this region and therefore provides thenecessary break in the outer edge zone 34. A metal may be used in placeof polysilicon. Adjacent to the strip-shaped trench structure 25 in thecell field 4 and the flatness of the inner and outer edge zones 35 and34 respectively, FIG. 1 illustrates metallization surfaces for ametallization layer 32 for a source connection electrode 36, which inthis top view covers two fields of the surface of the semiconductordevice 1, and a simultaneously applied metallization layer 33 for a gateconnection electrode 37, which in the active cell field 4 connects theelectrodes 9 made of an electrically conductive material, which areillustrated in FIG. 4, to one another.

FIG. 2 illustrates a schematic representation of a cross-section throughthe section of the semiconductor device 1 along line A-A through a fieldplate 8 or trench structure 7. The line A-A initially runs from theouter edge zone 34 in the edge region 6 through the edge trench 10 andthen parallel to the elongated field plates 8 of the cell field 4 to thebody zones 13 in the body zone region 50. The section illustrated incross-section in FIG. 2 is the transitional region from a cell field 4to an edge region 6. The edge region 6 includes an edge zone 12, theedge zone 12 being divided into an outer edge zone 34 and an inner edgezone 35 by the edge trench 10 surrounding the cell field 4.

In the edge region 6, a breakdown voltage which is at least equal tothat in the cell field 4 has to be achieved.

To avoid a premature breakdown, an inner edge zone 35 of thisembodiment, which extends within the cell field 4 from the edge trench10 to outer body zones 49, is doped with a material of the sameconduction type as the body zones 13 of the cell field 4 and thereforehas a complementary conduction type and a p-n junction 47 to the n-typematerial of the drift zone 5 located below. For this purpose, the dopingmaterials have, during the production of the body zones 13, beenimplanted through a thinned field oxide 16 up to mesa structures of thecell field 4 of the semiconductor device 1 with its strip-shaped trenchstructures 7. As a result, the impurity concentration is lower in theinner edge zone 35 and the outer edge zone 34 than in the body zones 13.In addition, penetration depth is correspondingly reduced, as the bodyzones 13 are implanted while the front side 11 of the semiconductor body3 is completely free of oxide in the cell region 4. Nevertheless, as aresult the potential in the inner edge zone 35 is restricted to thesemiconductor body 3 and does not reach the field oxide 16. This isillustrated in FIG. 3 by using the plotted profile of the space chargezone in the off state.

It further has to be ensured that the outer edge zone 34 does not extendto the outer-most edge of the semiconductor chip. In this embodiment,this can be achieved by using the structure of a channel stopper asdescribed above, which at the same time serves as a masking structurefor the ion implantation of the doping materials of the complementaryconduction type, which are used both for the base zones 13 in the cellfield 4 and for the edge zone 12 in the edge region 6 as well aspartially in the cell field 4.

In the embodiment according to FIGS. 1, 2 and 3, the body zoneimplantation is designed such that it just extends through the oxide 16in the edge zone 12. The thickness of the oxide on the front side 11 ofthe edge zone 12 is expediently reduced by various process processes inthe course of the production of the semiconductor body 3, so that theoxide has a significantly reduced thickness at the time of the body zoneimplantation, which is now used to reach the edge zone 12 withcomplementary doping using doping materials of the ion implantation forthe body zone 13.

While a proposed thickness of the oxide layer is provided in the trenchstructure for the required blocking capability, the thickness of theoxide on the front side is less at the time of the body zoneimplantation. At a preset implantation energy, the body zone 13 can nowbe produced within the active cell field 4, while at the same time, asillustrated in FIGS. 2 and 3, a region of a complementary conductiontype of the inner and outer edge zones 35 and 34, respectively, isformed in the edge zone 12 on the front side 11. By suitably adjustingthe thickness of the field oxide on the front side, athrough-implantation of part of the p-doping is made possible, so that ap-doping is obtained in the critical region and a premature breakdown isprevented at this point.

FIG. 3 illustrates a perspective schematic representation of the sectionof the semiconductor device 1 according to FIG. 1 along line A-A througha body zone 3 or a mesa structure, wherein the section illustrated inFIG. 2 is viewed from the other side.

Comparative simulations with semiconductor structures withoutcomplementary doping in the inner edge zone 35 show with regard topotential distribution that the potential reaches upwards in the regionbetween the continuous edge trench 10 and the field plate 8 of the cellfield 4 in a conventional structure, while the inner edge zone 35 withits complementary doping efficiently pushes the potential, which followsthe form of the space charge zone indicated by a dot-dash line 51,downwards.

The potential is therefore not deflected towards the front side betweenthe last trench structure 7 of the cell field 4 and the edge trench 10,but is pushed downwards into the semiconductor body 3, and it does notreach the field oxide 16 even in the edge region 6 after the edge trench10, but is likewise displaced into the semiconductor body 3 by the p-njunction between the edge zone 12 with its complementary doping and thedrift zone-doped semiconductor material located below, as describedabove. This potential profile insures that avalanche generation isreduced in a breakdown situation and remains restricted to the lowertrench region 45 up to the active cell region without jumping to thefront side 11 of the semiconductor body 3. As a result, an improvementis achieved in a breakdown situation owing to reduced avalanchegeneration, in particular owing to the fact that the curvature of thep-n junction at the body end 49 is unloaded and the major part of theavalanche generation is found at the trench base 46 in an embodimentwith an existing p-type region.

The semiconductor devices structured according to FIGS. 1 to 3 arecharacterized by a noticeably improved potential profile, and avalanchegeneration can be reduced even in a breakdown situation, because thecurvature of the p-n junction at the body zone end 49 is unloaded andthe major part of avalanche generation is found at the trench base 46 ofthe edge trench 10 in an embodiment with an existing inner edge zone 35of a complementary conduction type.

Simulations show a significant improvement of the potential profile andan increased electric strength in the region of the edge trench 10. Thisfurther improves the performance of the semiconductor device, whichfinds expression in a significant reduction of stationary losses in theon state.

In place of an implantation of impurities for the inner edge zone 35synchronous with the implantation of the body zones 13, a separate ionimplantation can be provided for the inner edge zone 35, in particularif the orientation and characteristics of the body zones 13 are not tobe changed in a predetermined cell structure in the cell field 4. In asecond ion implantation of this type, the energy used is chosen suchthat the thick oxide in the region of the inner edge zone 35, which hasbeen applied, is penetrated. The dose may however be significantly lessthan the dose for the body zones 13 and only has to cause a re-doping ofthe n-type region in the inner edge zone 35 near the front side 11 ofthe semiconductor body 3. This separate, additional implantation for theproduction of an inner edge zone 35 of a complementary conduction typemay be carried out immediately following the body zone implantation, orelse following the driving-in using a diffusion process of the bodyzones 13.

In such an additional implantation process, an interruption of thegenerated p-type region of the outer edge zone 34 up to the edge of thesemiconductor chip has likewise to be insured as described above, andthe complementary doping of the edge zone 12 has to be sufficient inorder not to be depleted by the drain potential. The inventive principleof an edge zone 12 of a complementary conduction type below the fieldoxide 16 can be applied both to n-channel MOSFETs and to p-channelMOSFETs.

In the embodiment according to FIG. 3, the body zone implantation isdesigned such that is just extends through the oxide 16 in the edgeregion 6. At the time of the body zone implantation, the thinning of theoxide 16 on the front side 11 during the preceding process steps issufficient for a penetration of the oxide 16 using the doping materialsof the body zones 13. However, as the thickness of the oxide 16 in eachfield plate trench determines the blocking capability of the transistor,the body zone implantation is individually adapted to suit the differentblocking classes, in order to ensure the formation of an edge zone 12,in particular the inner edge zone 35, of a complementary conductiontype.

FIG. 4 illustrates a diagrammatic cross-section through the section ofthe semiconductor device 1 according to FIG. 1 along line B-B. Thesection illustrated in cross-section in FIG. 4 is a transitional regionfrom the cell field 4 to the edge region 6. Of the cell field 4, a lastfield plate 8 and two trench gate structures 9 surrounding the fieldplate 8 are illustrated. The trench structure 7 of the cell field 4 istherefore provided with a field plate 8, which may for example besurrounded by two gate electrodes 23 and 24 adjacent to the field plate8.

As FIG. 4 illustrates, the trench structure 7 is, in the cell field 4 onthe trench walls 27, provided with an oxide layer 26 for insulation inthe lower region 45 of the trench structure 7 and thus of the fieldplate 8. In the cell field 4 and in the edge trench 10, the field plate8 is made of a conductive material 38. In the upper region 28 of thetrench structure 7 in the cell field 4, a gate oxide 18 insulates thetrench gate electrodes 34 and 24 from a base zone 13 located in theupper region of the semiconductor body 3. The conduction type of thisbase zone 13 complements that of the drift zone 5 located below.

Finally, there are source zones 19 located near the front side 11 of thesemiconductor body 3 in the cell field 4; these have the same conductiontype as the drift zones 5, but are doped more highly. When a suitablepotential is applied to the trench gate electrodes 23 and 24, a channel44 forms in the body zone 5 to create a connection between the sourcezone 19 and the drift zone 5, enabling a current to flow from the sourcemetallisation layer 32 through a via 21 from a contact hole 31 to adrain zone 50, the cell region 4 gating in this process.

The edge trench 10 illustrated in FIG. 4 includes a field plate 14 atsource potential, which is insulated from the surrounding semiconductormaterial of the semiconductor body 3 by a field plate insulation 15. Thefield oxide 16 on the edge zone 12 of a complementary conduction type isless thick in the process of body zone implantation than the field plateinsulation 15 of the edge trench 10. As FIG. 2 illustrates, the edgetrench 10 may divide the edge zone 12 of a complementary conduction typeinto two zones, these being the inner edge zone 35 between the cellregion 4 and the edge trench 10 and an outer edge zone 34 from the edgetrench 10 to a continuous annular channel stopper illustrated in FIG. 1,which in the present case is at drain potential, or to an annular layernot illustrated in the drawing, which masks the ion implantation. Inthis embodiment, the edge zone 12 of the complementary conduction typeextends laterally from a channel stopper of a conductive material, whichsurrounds the semiconductor chip, via the edge trench 10 to the marginalbody zones 49 of the cell field 4, virtually extending into the marginalbody zones 49 of the cell field 4.

FIGS. 4 a to 4 c illustrate diagrammatic cross-sections through fieldplates 8 in the cell field 4 with different gate structures 61, 62 and63 in the same trench.

FIG. 4 a illustrates a diagrammatic cross-section through a field plate8 in the cell field 4 with two gate electrodes 23 and 24 of a first gatestructure 61, which can already be seen in FIG. 4. Components of thesame function as those in FIG. 4 are identified by the same referencenumbers and not explained again. If a suitable gate voltage is applied,the gate electrodes 23 and 24 cause the formation of two channels 44 inthe body zones 13 between a highly doped n′-type source zone 19 and lesshighly doped n⁻-type drift zones.

FIG. 4 b illustrates a diagrammatic cross-section through a field plate8 in the cell field 4 with a joint gate electrode 23 of a second trenchgate structure 62. If a suitable gate voltage is applied, the gateelectrode 23 causes the formation of two channels 44 extending on eitherside of the second trench gate structure 61.

FIG. 4 c illustrates a diagrammatic cross-section through a field plate8 in the cell field 4 with two separate gate electrodes 23 and 24 of athird trench gate structure 63. In the region of the gate electrodes 23and 24, however, there is no electrically conductive field platematerial, but rather an insulating material. If a suitable voltage isapplied to the gate electrodes 23 and 24, two conductive channels 44 areformed in the body zones 13 between a highly doped n′-type source zone19 and less highly doped n⁻-type drift zones.

FIGS. 5 to 13 illustrate cross-sections along a line B-B of FIG. 1through a section of a semiconductor body 3 in the process of theproduction of the device 1 according to FIG. 1.

FIG. 5 illustrates a diagrammatic cross-section through a section of asemiconductor body 3 after the introduction of trench structures 7.These trench structures 7 are introduced into an n-type drift zonematerial in this embodiment; in this process trench walls 27 are formedand mesa structures 39 remain standing in the cell field 4 made of asemiconductor body material. The trench structures 7 and the mesastructures 39 are then coated with a silicon oxide layer by oxidation ofthe silicon, with the result that, as illustrated in FIG. 6, a siliconoxide acting as an insulating layer covers the front side 11 of thesemiconductor body 3. As an alternative, an insulating material can bedeposited from the gas phase. The insulating material may also beapplied in several layers.

FIG. 6 illustrates a diagrammatic cross-section through the section fromFIG. 5 after the application of an insulating layer 26. This insulatinglayer 26 forms a field oxide 16 on the top of the mesa structures and,on the trench walls 27, an insulating layer for field plates to beinstalled.

FIG. 7 illustrates a diagrammatic cross-section through the section fromFIG. 6 after the trench structure 7 has been filled with a conductivepolysilicon material 38. In place of the conductive polysilicon material38, a conductive metallic material could be applied to the insulatinglayer 26 in the trench structure 7. In this process, the front side 11of the semiconductor body 3 is simultaneously coated with a conductivepolysilicon material or a conductive metallic material. As FIG. 8illustrates, this is later removed from the front side 11 of thesemiconductor body 3.

FIG. 8 illustrates a diagrammatic cross-section through the section fromFIG. 7 after the removal of the polysilicon material or the conductivemetallic material from a field oxide 16 on front sides 11 of mesastructures 39. Now both the cell field 4 and the edge trench 10 havefield plates 8 insulated from the semiconductor body 3. While the fieldplates 8 in the cell field 4 are strip-shaped as illustrated in FIG. 1,the edge trench 10 with its field plate 14 surrounds the entire cellfield 4.

FIG. 9 illustrates a diagrammatic cross-section through the section fromFIG. 8 after the application of a photoresist covering 41 to the fieldoxide 16 in the edge regions 34 and 35. The mesa structures 39 on thefront side 11 of the semiconductor body 3 are, however, not yet exposed,because these regions are still covered by the field oxide 16.

FIG. 10 illustrates a diagrammatic cross-section through the sectionfrom FIG. 9 after the removal of the field oxide 16 above the cell field4 and the etching in the trench. This exposes an upper region 28 of thetrench structure in the cell field 4, allowing the trench gatestructures to be introduced here while the trench ends 45 remainsurrounded by the field oxide.

FIG. 11 illustrates a diagrammatic cross-section through the sectionfrom FIG. 10 after the removal of the photoresist covering on the edgezones 34 and 35, after the application of an insulating region 42 aroundthe upper region of the field plate 8 and after the introduction oftrench gate structures into the upper region 28 of the trench structuresin the cell field 4. These upper regions 28 of the trench structures arenow provided with a gate oxide 18 and gate electrodes 24 of a conductivematerial on the trench walls 27, an oxide layer 42 insulating the fieldplates 8 from the gate electrodes 9.

For this purpose, the upper region 28 of the trench structure 7 in thecell field 4 is filled with a conductive material, wherein for examplethe whole front side 11 of the semiconductor body 3 is covered with apolysilicon material or a conductive metallic material, which issubsequently removed from the front side, whereby mutually insulatedtrench gate structures 9 are created in the upper region 28 of thetrench structure 7 in the cell field 4.

FIG. 12 illustrates a diagrammatic cross-section through the sectionfrom FIG. 11 after the removal of the gate oxide layer 18 on the frontside 11 of the semiconductor body 3, followed by ion implantation. Byion implantation in the direction of the arrows A and a subsequentdiffusion process, the body zones 13 illustrated in FIG. 12 are created,while the edge zones 34 and 35 of a conduction type complementing thatof the drift zones 5 are created in the edge zone 12. As explainedabove, the edge zone 12 of the complementary conduction type can beintroduced at a later point in time, but the oxide thickness values inthe edge region 6 have already been almost doubled, with the result thata separate ion implantation for the edge zones 12 would involve a higherimplantation energy but a lower dose than the implantation of the bodyzone region. In either case, the channel stopper region illustrated onlyin FIG. 1 is capable of interrupting the outer edge zone 34 in the edgeregion 6 up to the edge of the semiconductor chip.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat a variety of alternate and/or equivalent implementations may besubstituted for the specific embodiments shown and described withoutdeparting from the scope of the present invention. This application isintended to cover any adaptations or variations of the specificembodiments discussed herein. Therefore, it is intended that thisinvention be limited only by the claims and the equivalents thereof.

1. A method of producing an integrated circuit device, comprising:forming a trench structure having trench walls in a semiconductor bodyfor a cell field and an edge trench in an edge region; forming mesastructures for drift zones of a first conduction type in the cell field;applying an oxide layer forming a field plate isolation on the trenchwalls and a field oxide in the edge region of a front side of thesemiconductor body; introducing field plate material into the trenchstructure and the edge trench; exposing upper regions of the trenchwalls in the cell field; applying a gate oxide to the exposed upperregion of the trench walls; introducing a gate electrode material intothe upper regions of the trench structure; and ion implantation ofdoping materials for a complementary conduction type accompanied by theformation of body zones on the mesa structures in the cell field and bythe formation of an edge zone of a complementary conduction type withdoping materials of the body zone below the field oxide in the edgeregion within and outside the edge trench.
 2. The method of claim 1,wherein the trench structure for the cell field and the edge is producedby means of a single etching step.
 3. The method of claim 1, wherein aninsulating layer which forms a field plate insulation on the trenchwalls and an insulator in the edge regions of the front side of thesemiconductor body is applied by a thermal oxidation of a siliconsemiconductor material and/or by means of the deposition of an insulatormaterial.
 4. The method of claim 1, wherein the field plate material isintroduced into the trench structure and the edge trench by introducinga conductive material or a metal alloy into the trench structure and theedge trench.
 5. The method of claim 1, wherein the field plate materialis introduced into the trench structure and the edge trench by means ofpolysilicon deposition.
 6. The method of claim 1, wherein a continuousannular channel stopper is implemented at the lateral end of the edgezone prior to the introduction of the doping materials of the bodyzones, said channel stopper acting as a masking limit for an ionimplantation of the edge zone of the complementary conduction type. 7.The method of claim 1, wherein the upper region of the trench walls inthe cell field is exposed by a selective oxide layer wet etching processfollowing the covering of the field oxide to be protected in the edgeregion.
 8. The method of claim 1, wherein the upper region of the trenchwalls in the cell field is exposed by a selective oxide layer dryetching process following the covering of the field oxide to beprotected in the edge region.
 9. The method of claim 1, wherein a gateoxide is applied to the exposed upper region of the trench walls by athermal oxidation of the exposed semiconductor material.
 10. The methodof claim 1, wherein gate electrode material is introduced into the upperregion of the trench structure by depositing a conductive material inthe upper region of the trench structure.
 11. The method of claim 1,wherein, for the ion implantation of doping materials for acomplementary conduction type accompanied by the formation of body zoneson the mesa structures in the cell field and by the formation of an edgezone of a complementary conduction type with a body zone doping belowthe field oxide in the edge region, boron ions are implanted from thefront side of the semiconductor body.
 12. The method of claim 1, whereinfor the ion implantation of doping materials for a complementaryconduction type, a first implantation step is first carried out for theformation of body zones on the mesa structures in the cell field,followed by a second implantation step for the formation of an edge zoneof a complementary conduction type with a body zone doping below thefield oxide in the edge region.
 13. The method of claim 1, wherein theconcentration of doping material of the edge zone of the complementaryconduction type is matched to the relevant breakdown voltage class of apower semiconductor device.
 14. The method of claim 1, wherein thefollowing is carried out on a semiconductor wafer to complete thesemiconductor device: introduction of source zones with a higherconcentration of doping material than the drift zones into regions ofthe body zones: application of a further structured insulating layer;introduction of contact holes for vias into the cell field for bondingthe source zones, body zones and field plates; introduction of contactholes for vias into the cell field for bonding the trench gatestructure; application of a structured metallization layer while jointlybonding the source zones, body zones and field plates, accompanied bythe formation of a source connection electrode, the bonding of thetrench gate structure and the formation of a gate connection electrode;division of the semiconductor wafer into semiconductor chips; andinstallation of at least one semiconductor chip into a housing toproduce a semiconductor device.